Fiber-optic sensors have been utilized in a number of applications, and have been shown to have particular utility in sensing parameters in various environments. Optical fiber sensors can be incorporated into environments such as downhole environments and be used to sense various parameters of an environment and/or the components disposed therein, such as temperature, pressure, strain and vibration. An exemplary temperature sensing system is a Distributed Temperature Sensing (DTS) system, which utilizes fiber optic cables or other devices capable of measuring temperature values at multiple locations along the length of a wellbore. DTS can be used to measure, for example, a continuous temperature profile along the wellbore.
Some Distributed Temperature Sensing (DTS) systems for use downhole utilize Spontaneous Raman Scattering (SRS) in optical fibers to measure temperature. The relative amount of Stokes and Anti-Stokes light generated by SRS is dependent on temperature. The Stokes and Anti-Stokes wavelengths differ from the initial laser wavelength and so can be separately detected and compared in order to compute the temperature along the fiber. Errors in calibration can occur as a result of conditions other than temperature causing changes in loss of the Stokes and anti-Stokes wavelengths.